Update From Wayback: AVGA Reborn as RetroWiz

retrowiz-vga-avr-gaming-system

This one has been a long time coming. We’re finally seeing an update to [Jaromir's] retro gaming platform based around and ATmega chip. The thing that was novel about it back in 2009, and continues to be to this day, is the use of VGA output (PAL) from an AVR chip rather than composite video like most offerings.

Good projects never die and recently he picked the hardware up again, spinning a mostly surface mount board and putting together a new website to feature his work. Above you can see a demo of Commander Keen 4 running on the hardware (video below). He’s also has a rather trippy Super Mario port and adapted [Albert Seward's] PacMan source for the hardware.

The chip is being clocked at 32MHz with VGA clock running at 19.6608 MHz. This gives him sixteen colors with a resolution of 192×144. He concedes that you get better resolution out of composite video, but who needs resolution for retro gaming?

Comments

  1. Ralph says:

    The schematic shows a 32Mhz crystal being used. I wonder if that’s a typo?
    http://prometheus4.com/retrowiz/images/img/sch.png

    • rj says:

      Given that he explicitly mentions an 8MHz dotclock in the video, I bet the 19.6MHz is a typo.

      I understand the reasons for using CGA-style RGBI, but increasing the color depth would help a lot with the appearance. The PCjr/Tandy 1000 160×200 mode was rather ugly, but the biggest differences between this and other projects are the DAC, the not-using-an-NTSC-modulator, and the modeline. And the modeline is software…

  2. Jacqques says:

    VGA (PAL)? What PAL as to do with it?. PAL like NTSC is a composite vidéo standard. Looking at the schematic it is fact a VGA signal. I think the ‘PAL’ refer to fisrt version of AVGA which has been replaced by a VGA output in second version.

    • John U says:

      I was thinking that too. It’s possible to output PAL (or NTSC) rate video on a VGA interface, but most VGA monitors don’t like or support it – Amigas used to do this, the native output was PAL/NTSC but with a VGA adapter and “special” Multisync VGA monitor that supported such slow refresh rates you could display on a proper monitor.

  3. lp says:

    I wonder if all AVRs run flawlessly being overclocked to 32MHz.

  4. Tom the Brat says:

    Commander Keen? Oh! I’ve GOT to do this!

  5. James Bowman says:

    Hadn’t seen this pacman version before. Just ported it to Arduino+Gameduino 2:

    https://github.com/jamesbowman/gd2-pacman

  6. Rob says:

    I love these retro computers but none of them are quite what I want. This one is great in that it manages to squeeze 32 MIPS out of an ATMEGA.

    I have been deciding on what to base a similar project on. I want an ‘upgraded’ retro computer. I want to code in Z80 assembly. Real Z80’s are only about 5 MIPS so I would be better of writing a Z80 emulator to run on a modern chip.

    My basic requirements are (Q)VGA resolution of about 320×240 or 320×200, decent RAM 128K or better, PS2 keyboard/mouse and booting from a SD card formatted as FAT32. No NTSC or PAL, just using a normal VGA monitor.

    I don’t want to build complex hardware so I want to use something I can just plug into some vero board with the IO connectors. So yeah, I would have to bitbang the video.

    Most of the faster chips today have multiple internal buses running at different speeds and to add to the bit banging nightmare many of them have a pre-fetch cache that is hit an miss.

    The best I have seen so far is the Fubarino so I might give that a go.

    I want to keep it as low cost and easy to build as possible and hence the standard IO like PS2/VGA/SD, everyone has these lying around.

    Of course the same platform could be ported to other retro chips.

    I would love to know what others thing.

    Any tips appreciated.

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